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Flashcards in Object perception - VS Deck (70):
1

which area in the brain of a monkey is all purpose simple form & all object processors found

V4/IOT (inferior occipital temporal cortex)

2

which area in the human brain is all purpose simple form & all object processors found

LOC (lateral occipital cortex) area

3

in both monkey and human brain, where are more specialised object processors found for recognising faces and buildings

IT (inferior temporal), fusiform gyrus, several areas

4

in both monkey and human brain, where are more specialised object processors found for spatial scenes/places and navigating through them

IT (inferior temporal)/ParaHippocampal gyrus

5

which serial processing is used to rebuild the object image

from: V1/V2 - V4 - IOT - IT (where real objects are encoded)

6

what are the form processing cells in area v1 & v2 and what do they respond to

orientation selective
respond to lines & edges

7

where are the form processing cells located in area v1 & v2

in interblob zones of layers 2-4A & 5-6 (in v1)

8

what are the form processing RF sizes in area v1/v2

relatively small 0.1 (fovea) - 2 (bit eccentric) degrees, depending on visual eccentricity

9

what are the form processing RFs organisation like in area v1/v2

- simple ~15%: linear discrete ON & OFF sub-regions
- complex ~75%: non-linear, overlapping ON/OFF regions
- hypercomplex ~10%: end-stopped inhibition, so also size selective and well as orientation selective

10

what do RF organisations of form processing cells in area V1/V2 interested in

only like lines/edges of a particular orientation and hate ones that are at 90 degrees

11

how many % off cells in area v1 are orientation selective and what do they respond best to

75%
respond best to contours (lines, edges) over a narrow range of possible orientations but not to other orientations of the same stimulus

12

what are the orientation selectivity cells in area v1 responses independent of, and except which population

independent of the size of the oriented stimulus
except among a small population 5-10% of 'end-stopped' or hyper-complex cells

13

what two sub-divisions is monkey area V4 believed to contain

1. one primarily concerned with colour vision
2. other mainly concerned with form vision

14

what are the RFs of the sub division of monkey area v4 concerned with form vision size, compared to area v1 at equivalent visual field locations

2-5x larger

15

what component is 2-5x compared to another component in a monkey brain

the RFs of the sub division of monkey area v4 concerned with form vision size, compared to area v1 at equivalent visual field locations

16

what does monkey area v4 sub-division concerned with form vision, contain none of, and only of which RF organisations

no simple cells (beyond v1 & v2)
all RF organisations are complex or many are hyper-complex (end-stopped)

17

in monkey area v4 sub-division concerned with form vision what are ~50% of cells

orientation selective
but they ALL prefer stimuli of a particular size (width verses length)

18

what do the ~50% of orientation selective cells in monkey area v4 sub-division concerned with form vision all prefer

stimuli of a particular size (width verses length)

19

how is RF sizes in functional specialisation for object & motion perception areas V4, IOT & IT compared to V1 cortex

increased RF sizes at all eccentricities (neurons analysing a larger region of space)

20

how is orientation selectivity in functional specialisation for object & motion perception areas V4, IOT & IT compared to V1 cortex

reduced orientation selectivity and absent in IT
replaced by size-shape or object category-selectivity

21

what are orientation selectivity in functional specialisation for object & motion perception areas in V4, IOT & IT replaced by

size-shape or object category-selectivity

22

how are the specific form attribute in functional specialisation for object & motion perception areas V4, IOT & IT compared to V1 cortex

columnar organisation for that specific form attribute that the area is responsible for and specialised to encode

23

how are the representation of central vision where perception mainly occurs in functional specialisation for object & motion perception areas V4, IOT & IT compared to V1 cortex

biased representation of central vision, where object perception mainly occurs, in object processing pathway areas only concerned with central vision, central 20 degrees where we identify & recognise objects and peripheral VF representations disappear the higher up the pathway you go

24

how is the retinotopic order in functional specialisation for object & motion perception areas V4, IOT & IT compared to V1 cortex

loss of retinotopic order

25

what does RF sizes increase with for V1, V2, V4 & IOT & IT cells

eccentricity, by a linear correlation

26

what does the increase in size of RF with eccentricity increase gradually from

V1 to V2 to V4 & becomes really large in IT & IOT cortex

27

what is the increase in RF size in V1 V2 V4 & IT & IOT mirrored by

increase in RF complexity

28

what are V1 and V2 RFs mainly concerned with

fragments of objects (lines and edges)

29

what are V4 and IT & IOT RFs mainly concerned with

simple geometric shapes & real objects and complex shapes (components of objects)

30

what are most of the ~50% of v4 cells which are orientation selective

end stop tuned
to the size of the stimulus (like hyper column v1 cells)
where e.g. in a box RF, a line placed inside it must be confined to the RF size, if extended the RF will shut off

31

what do the other of the ~50% of v4 orientation selective cells which are not end stop tuned respond to

respond selectively to simple geometric shapes (squares, rectangles) of a particular size e.g. can like a small rectangle placed in its RF, or a square placed in its RF or a rectangle placed in its RF..

32

what do monkey IOT & IT cortex RF properties of single cells correlate with

object perception

33

what are the monkey IOT & IT RFs like in relation to V4 RFs

much larger than V4 RFs & always involve the fovea & central (10-20 degrees) visual field

34

what do the monkey IOT & IT RFs always involve

the fovea & central (10-20 degrees) visual field

35

what do the monkey IOT & IT RFs cells respond to what type of stimulus

a specific form stimulus anywhere in their RF & regardless of its size

36

what do IOT cells respond to

general shapes like squares or triangles, or to particular patterns

37

what do IT cells respond to

only category-specific objects, like faces, hands or types of fruit

38

what are the names of the dots/plots on a graph which shows a share cell in IOT response to particular shapes

rastor plots, the more there are, the more the IOT likes that shape i.e. stimulus fires lots of action potentials

39

why are there rows of dots on the graphs which shows the amount of rastor plots of a shape cell in the IOT cortex e.g. a row of 8 dots

indicates that the stimulus was placed into the cell's RF on 8 separate occasions to look at the cell's response to make sure the activity produced by one stimulus presentation was reliable and consistent from one to the next

40

what does an accumulative histogram show of a shape cell in IOT cortex

the number of action potentials that were fired shortly after the stimulus was presented, so a big mountain = a big response and no mountain = no response

41

what does a histogram of different types of squares of a shape cell in IOT cortex results investigate

if its components of a square which fires action potentials and shows e.g. the cell may not like a square with a hole in the middle or patterned stripe squares, but may like the solid square

42

what type or organisations are there for neurons in IOT cortex

columnar

43

what do the vertical columns represent for neurons in IOT cortex

response of cells are the same to those types of stimulus can be, simple geometric and complex shapes, hands or patterns

44

what do horizontally across the cortex cells represent in IOT cortex

types of cells you find are different preferences

45

what does a recording from a monkey face cell in IT cortex show

that it can only respond to one face of interest where it gives a big response (out of 4 faces which was placed in its RF, the responses were completely different and depended on the face that was placed there) regardless of the viewing angle or facial expression

46

in the ventral, what? processing stream, where is area v4 located

on the lingual gyrus

47

what does area v4 in the ventral what? processing stream represent

form & colour

48

in the ventral what? processing stream, where is the IOT/LOC located

inferior temporal sulcus and gyrus

49

what does the IOT/LOC in the ventral, what? processing stream represent

all objects, general object processor

50

in the ventral, what? processing stream, what does the IT/fusiform gyrus represent

specific objects (faces)

51

when images of a banana vs scrambled version of banana (stimulus) was presented to a person and the activity of the brain was monitored, what was the difference in cortical action with the LOC, compared to area V1

LOC only activated with the real object - banana
V1 was not activated when viewing banana vs scrambled version as cells in V1 like oriented lines in the scrambled version and the blocks and edges too

52

what type of objects is the LOC activated by

all types of objects

53

what area is only activated by faces

face area on fusiform gyrus (not interested in objects)

54

what usually happens in a general form agnosia (damage to LOC)

- conscious visual sensation of the components of objects is preserved (because area v1 & v2 is intact)
- but px cannot recognise whole objects that they see or understand their meaning (what they are and what they're there for)
- although memory of what they look like & their purpose are preserved

55

what usually happens in category-specific agnosia (damage to fusiform gyrus)

- is restricted to particular classes of object
- most commonly faces = prosopagnosia, but can be just animals or buildings etc which can be damage to areas right near the fusiform gyrus

56

what can be seen in form agnosia, damage to LOC

lines and contours and other elements due to v1 being intact

57

what cannot be understood in form agnosia, damage to LOC

the over all picture, what it is

58

what can carbon monoxide poisoning effect

inferior occipital & temporal parts of the brain and can cause a bilateral LOC lesion

59

what remains intact from a LOC lesion

- visual fields
- VAs, stereo
- spatial acuity
- colours
- motion

60

what cannot be matched with a person with LOC lesion

simple shapes or simple objects
nor can they copy-draw familiar objects but can reproduce-draw them from memory

61

what can people with prosopagnosia: damage to fusiform gyrus not recognise

faces, including their own

62

what can people with prosopagnosia: damage to fusiform gyrus identify

familiar people from other visual cues e.g. hair colour, spectacles & from their voice
can also interpret emotions in facial expressions, even though unable to identify to whom the face belongs to, as this involves another part of the brain called the amygdala

63

what are the physical properties of real objects e.g. your own face

invariant, they are immune to changes n ambient illumination, viewing angle, size, location

doesn't change from moment to moment, regardless of other things that do change

64

what is the fundamental challenge of the perceptual ventral stream

is to create object-based representations of the physical constancies, while ignoring these other random factors e.g. when light levels drop

65

extra striate cortex contains neurons that represent...

object constancies e.g. faces, regardless of their viewing angle, location, size or expression

66

but what do the perceptual constancies for object forms, colours & motion seem to be represented in

different, widely separated (located in different parts) extra striate cortical areas

67

what are objects with similar features (faces or volkswagons) represented by

many single cells as a 'population code' e.g. face cells in IT cortex respond to several faces with similar features, not just to one (such as cells in a monkey brain tend to encode particular categories of people, e.g. some cells like people with narrow thin noses with eyes close together but hate, people with round flat noses with eyes wider apart and vise versa) so has category specific rather than groups of faces in the IT cortex

68

in the extra striate cortex, only damage to the fusiform gyrus can cause...

prosopagnosia

69

in the extra striate cortex, none of which cells are orientation selective

LOC cells

70

in the extra striae cortex, damage to area V5/MT in the left cortex would result in...

right hemi-akinetopsia